Abstract
1. Two g of thiamine was decomposed by crude thiaminase of clam viscera. The several pyrimidine derivatives formed were separated by gradient elution using Amberlite XE-64.
2. Three kinds of pyrimidine derivatives were isolated in a crystalline form. One was proved to be indentical with 2-methyl-4-amino-5-hydroxymethylpyri-midine hydrochloride. Both of the other two pyrimidine derivatives gave the RF values lower than that of thiamine, had an absorption maxima at 237 and 279mμ at pH 6.5, changed its absorption spectrum with the change of pH of the medium.
